Description
I do not know if there are already online services for this but you can copy some tables online, paste them into ChatGPT and ask it to make a markdown table from that.
You can then copy and paste that into some markdown-compatible apps like Notion.
ChatGPT will even create headers for the table as it knows how to classify information. However, it might invent headers with the wrong categories as in the example below
I did not test this much to know if it ever makes mistakes.
Example
The table below was copy pasted from the Wikipedia page :List of cities proper by population density. Those three cities happen to be at the top of the table
Prompt
provide markdown to make the table below:
Manila 1,846,513 43 17 43,062 111,532 Philippines * 2020 [1] 2018[2]
Mandaluyong 425,758 11 4 38,495 99,703 Philippines * 2020 [1][3]
Pateros 65,227 2 1 37,061 95,988 Philippines * 2020 [1] 2013[3]